i386: -Wabi false positive with indirect call [PR60336]

This warning relies on the TRANSLATION_UNIT_WARN_EMPTY_P flag (set in
cxx_init_decl_processing) to decide whether we want to warn about the GCC 8
empty class parameter passing fix, but in a call through a function pointer
we don't have a translation unit and so complain for any -Wabi flag, even
now long after this was likely to be relevant.

In that situation, let's check the TU for current_function_decl instead.
And if we still can't come up with a TU, default to not warning.

	PR c++/60336

gcc/ChangeLog:

	* config/i386/i386.cc (ix86_warn_parameter_passing_abi):
	If no target, check the current TU.

gcc/testsuite/ChangeLog:

	* g++.dg/abi/pr60336-8a.C: New test.

diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 2f8403381384bc6c3a224af0b3415770ff917f10..cb348cb9cfb8540b7c50a64c67c9befeff82e6d3 100644 (file)
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -18084,9 +18084,14 @@ ix86_warn_parameter_passing_abi (cumulative_args_t cum_v, tree type)
   if (cum->decl && !TREE_PUBLIC (cum->decl))
     return;
 
-  const_tree ctx = get_ultimate_context (cum->decl);
-  if (ctx != NULL_TREE
-      && !TRANSLATION_UNIT_WARN_EMPTY_P (ctx))
+  tree decl = cum->decl;
+  if (!decl)
+    /* If we don't know the target, look at the current TU.  */
+    decl = current_function_decl;
+
+  const_tree ctx = get_ultimate_context (decl);
+  if (ctx == NULL_TREE
+      || !TRANSLATION_UNIT_WARN_EMPTY_P (ctx))
     return;
 
   /* If the actual size of the type is zero, then there is no change

diff --git a/gcc/testsuite/g++.dg/abi/pr60336-8a.C b/gcc/testsuite/g++.dg/abi/pr60336-8a.C
new file mode 100644 (file)
index 0000000..a051843
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/pr60336-8a.C
@@ -0,0 +1,15 @@
+// { dg-do compile }
+// { dg-options "-O2 -Wabi=12" }
+
+struct dummy { struct{} a[7][3]; };
+
+extern void test1 (struct dummy, ...);
+extern void (*test2) (struct dummy, ...);
+
+void
+foo ()
+{
+  struct dummy a0;
+  test1 (a0, 42);
+  test2 (a0, 42);
+}